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KMID : 0371319690110110752
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Journal of the Korean Surgical Society
1969 Volume.11 No. 11 p.752 ~ p.757
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Radioautography as a Clinical Application
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尹健鎬/Youn, Kun Ho
南周鉉/朱剛/崔昌祿/朴元學/Nam, Ju Hyun/Joo, Kang/Choi, Chang Rok/Park, Won Hark
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Abstract
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In contrast to the considerable volum of biochemical investigation in tracing radio-elements in the body, very much attention has been paid to their histological localization. A method, however, was developed by Lacassagne and Latte´s(1924) for the demonstration of polonium in tissue sections. More recently, methods were devised to locate radioactive iodine in the thyroid gland(Leblond,1943). In these various techniques, advantage was taken of the fact that photographic film or emulsion sensition are sensitive rays. If therefore, histological sections of a tissue containing a radioactive element were juxtaposed to a photographic film or emulsion, an image appeared on the negative. A comparison of these images, so-called "autographs, " to the histological slides themselves, demonstrated the localization of the radio-element.
Recent studies(Hushes et al. 1958)have shown that thymidine, a specific DNA precursor, is selectively taken up by cells synthesizing new DNA in preparation for cell division. The injection of tritiated thymidine and the use of radioautography to identify cells which take it up provide a powerful tool for the study of cell proliferation. Further, since ³H-thymidine incorporated into DNA is metabolically stable, cells once labeled can be followed in their migrations and even through changes of cell type. After injection into animals tritiated thymidine is distributed by the blood stream and finds its way into cells. It is then incorporated into DNA by those cells that are in a suitable metabolic state, and thymine not utilized is broken down.
In our experiment pre- and postnatal mice were given intraperitoneal or intravenous of 5 uc. tritiated thymidine and killed each at a different interval between 1 hour to 26 hours. After dissection, organs were fixed in Bouin´s solution, embedded in paraffin, and sectioned.
The autoradiograms were prepared by a slight modification of the method described by Leblond(1957) and Langman(1698). The labeling index and the percentage of labeled mitosis were calculated(See table 1). Many cell populations of the body are constantly turn over, this cell loss is blanced by cell birth. This type of cell system is said to be in a dynamic equilibrium. In a cell population which constantly is being renewed, e. g. , in the epithelium lining the intestinal tract, individual cells divide periodically. This process of mitosis and interphase (periods between cell divisions) is termed the cell cycle. The duration of these cycle for any particular cell type now can be estimated accurately. Toward the end of interphase, DNA is synthesized, this being called the DNA duplication or the S stage. After the S stage, the cell enters a relatively quiescent period prior to mitosis called the post-duplication or G2 stage and then passes through prophase, metaphase, anaphase, and telophase. At the termination of mitosis, the daughter cells enter the pre-duplication or GI stage of interphase, which lasts until DNA duplication occurs prior to the succeeding mitosis. The length of the cell cycle varies obviously with the cell type, being, for example, short in the case of the epithelium lining the gut, relatively short in malignant tumor cell than that of normal cells and much longer in the liver cell and cardiac muscle cell.
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KEYWORD
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